The present invention generally relates to integrated circuits, and more particularly, to a system for preventing tampering of an integrated circuit.
Integrated circuits (ICs), such as those used in set-top boxes, engine control units (ECUs), and cryptographic systems, often store sensitive information including personal data, financial transaction authorization codes, security passwords, and secure session keys, and thus are prone to unauthorized access. A known technique to gain access to information stored in an IC is micro-probing. Micro-probing involves forming an electrical contact with the IC by placing fine-tipped probe needles directly on the point of interest of the IC, or on an area of the IC to which the point of interest is connected. The probe needles are held by a micro-manipulator that is controlled to precisely land the probe needle on the IC.
To protect ICs from micro-probing, static wire meshes have been designed that are placed close to the ICs. In a static wire mesh, first and second wires are respectively connected to power and ground, laid out in a mesh pattern, and monitored by a tamper detection module, which detects if either of the wires is broken, which it takes as an indication of an unauthorized attempt to probe the integrated circuit. For example, contact of the a probe needle with either of the wires causes corresponding tampering lines to be activated, which in turn sets off a self-erase sequence that erases the sensitive information in the IC.
Certain ways have been devised to bypass the static wire mesh in order to probe the integrated circuit, so active wire meshes have been deployed, where a serial bit stream is run through wires that form a mesh. It is much more difficult to compromise an active wire mesh. Even so, it would be advantageous to have a more robust circuit protection system.